Under the behavioural interpretation of lower previsions [1]}, where the lower prevision of a gamble is interpreted as the supremum price for buying that gamble, \(\underline{P}_{}(g-f)>0\)  means that our subject is willing to pay a strictly positive price for the gamble \(g-f\) , or equivalently, that she is willing to pay a strictly positive price to replace the uncertain reward \(f\)  by \(g\) .
